dmaengine: tegra-apb: Support per-burst residue granularity
Tegra's APB DMA engine updates words counter after each transferred burst
of data, hence it can report transfer's residual with more fidelity which
may be required in cases like audio playback. In particular this fixes
audio stuttering during playback in a chromium web browser. The patch is
based on the original work that was made by Ben Dooks and a patch from
downstream kernel. It was tested on Tegra20 and Tegra30 devices.
Link: https://lore.kernel.org/lkml/20190424162348.23692-1-ben.dooks@codethink.co.uk/
Link: https://nv-tegra.nvidia.com/gitweb/?p=linux-4.4.git;a=commit;h=c7bba40c6846fbf3eaad35c4472dcc7d8bbc02e5
Inspired-by: Ben Dooks <ben.dooks@codethink.co.uk>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20190705150519.18171-1-digetx@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
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